Ovulation Calculator

What is an ovulation calculator and how does it help you get pregnant?

Each month, there are only a few days when you have the highest chances of getting pregnant. These are the days around ovulation, which is the time your ovary releases a tiny egg that is ready to be fertilised by a sperm.

You can use your menstrual cycle (periods) to guess when you might be ovulating, and therefore having your most fertile days of the month.

How to use our ovulation calculator

Just tell us the date of your last period, and how long your cycle usually lasts. Then our ovulation calculator will estimate your most fertile time. Remember, it’s only an estimate, especially if your periods aren’t always regular.

When was the first day of your last period?

Adjusted cycle length: If you know that your cycle is shorter or longer than 28 days, please adjust the number below.

I have irregular periods, how can I work out when I'm ovulating?

Ovulation usually takes place 10-16 days before your period starts so if you have a regular cycle you can work out when you're likely to be ovulating from that. However, there are other ways to work out when you're ovulating, including:

1. Your cervical mucus; you may notice wetter, clearer and more slippery mucus around the time you're ovulating.

2. Your body temperature will rise a little during this time which you may be able to detect with a thermometer.

3. Hormone levels also increase in your urine around the time of ovulation and this can be detected using ovulation predictor kits that measure this.

How to boost your chance of conceiving

The best time of the month to get pregnant

If you’re just starting to try for a baby, try not to worry. About 8 in 10 couples get pregnant within a year if:

• The woman is under 40 years old

• They’re having regular sex

• They’re not using contraception.

You might decide to go with the flow for a while, but if you want to do more, it helps to know about your menstrual cycle, ovulation and your most fertile times:

• The average menstrual cycle is 28 days. But it’s not the same for every woman: it can be as short as 21 days or as long as 40 days. And it can vary for each individual woman, too, so your cycle might be different from month to month.

• Day 1 of your menstrual cycle is the first day of your period.

• Your ovary normally releases an egg between 10 and 16 days before your next period. This is your most fertile time.

It takes two to tango, so you have to think about the sperm as well as your eggs. An egg only lives 24 hours after it’s released. But a sperm can live around 5 days once it’s in the woman’s body, increasing the chances it will meet up with a live egg.

Did you know that long spells without sex can also mean fewer and less mobile sperm? That’s another reason why your best bet is to have sex throughout the month, at least every three days.

Your most fertile age

The most fertile age for women is between 19 and 26, when 92% of couples get pregnant within a year. Your fertility goes down gradually with age, so by the time the woman is between 35 and 39, the odds are 82%.

How to track your fertility

In addition to counting the days around your period and using our calculator, there are a few other ways to follow your body’s signs to find your most fertile times.

One method is to check your cervical mucus, which gets more clear, stretchy and slippery around the time you’re ovulating. This happens because it creates a good environment for sperm.

Some women take their temperature and chart it each day, because after ovulation your body temperature rises slightly and stays higher for the rest of your cycle.

There are also kits that tell you when you’re ovulating, by testing the hormone levels in your urine, and these are particularly useful if your cycle isn’t always regular.

Worried about not falling pregnant?

If you’ve been trying for a year and you’re worried about not getting pregnant, talk to your GP. If you’re 36 or older, or if you already know of a reason you might have fertility problems, see your GP sooner. There’s lots of help available and they’ll be able to give you advice on your next steps.

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The information on this website is for general information and it is not intended as, nor should it be considered as a substitute for seeing your own GP, midwife or healthcare professional. You are advised to seek professional medical advice if you have any concerns or suspect you have a medical problem.